I use to have this same problem.What you do is click on the misc option like you would and on a regular questline.Then you have to click on the specific misc quest for it to show on the map.What i mean by that if didnt understand is that you have o have the arrow things on both the misc option and the misc quest.Sorry if it doesnt make sense im not sure how to explain it.

If it truly is broken the guy you deliver those saphires to is in Riften, in the market place he is a lizard guy.

Yeah, that's just not working. I know what you mean, because I use that mapping for all the misc. missions, since that's about the only thing I've done. But for whatever reason that one just makes a thump noise and won't appear.
I thought maybe because it was the time of day. Maybe his shop wasn't open. But I've tried it all times of day. Now I'm starting to wonder if the guy is dead or something.
I'll head up to Riften tonight and look for him.